(Sec 1441 NRA foreign withholding tax)

I'm working in U.S Incorporated Company, as a tax analyst. I do analysis on foreign payments for to determine U.S sourced income which is gone out from U.S to foreign vendors. When I requested for the W-8 form from one of our foreign vendors, he provided W-9 form with foreign address, I questioned him W-9 form is for U.S citizens not for foreign vendors –He replied stating their company is incorporated in U.S. I was surprised W-9 form with foreign address; ideally this form should have been with U.S address right?...Will this form is fine?